Went with a Cadillac big block

Hey guys just updating you all in my direction of my build. My car is a 65skylark ht.. my plan was for a 455 but I'm on a budget and all the 455 blocks cost more than I can coin up. I decided to go with what's available and that was a Cadillac 472. It's from 73/74, I know it's not a Buick but with the distributor up front I'll have half them fooled. SkyLAC. Just an update.

After 71 the engines were rated differently, from the rear of the transmission with all the accessories running. The '71 Caddy 472 with the same compression ratio was rated the old way(off of the back of crank with no accessories running)@ 345 HP @ 4,400 RPM and 500 ft lbs @ 2,800 RPM!

Not sure why they didn't crank up the RPM on the later engines to get a better comparison but I would suspect that the engine didn't change from 71 when it was neutered and given 8.5:1 compression same as the year engine you have.

You shouldn't need a rear gear any bigger than a 3.08:1 with the torque of a 472, even with a 2.56 if that's what the car its going in has should run decent on the street. Anything over a 3.08:1 rear gear and with that amount of torque the car would be a tire shredder whenever the go peddle is stomped even when already driving!

Lots of upgrades can be done to that engine, the block can handle 2,000 HP without failing unlike a BBB! Of coarse it has its weaknesses like for instance the cast rods and cast pistons but the factory crank and block can handle 2,000 + HP!

Spectre performance made that much power with factory cast iron heads with twin turbos! They broke the single engine land speed record with a big block Cadillac engine in their Spectre Streamliner.

Thanks Lemmy! I love the Keep it simple method.. I am interested in a th400 switch pitch. What's a good source for one. I have been told on this forum that the 65/66 buicks have the Nailhead pattern and the 67 have the bop(c) trans pattern. Is this true for olds,pontiac and cadillac?. I've sourced a 65 cadillac th400 but don't know if it will bolt up.

Hey 300sbb_overkill WHAT'S UP BUD!!! I'm glad you didn't shune me for going cadillac you have been so helpful and cool to talk too. I appreciate you still trying to look out, as always I'll be taking your advise into high consideration, just some info but I picked it up for 300$ and
I want to know if you can look at this pic of the oil pump , why do you think it's disconnected, all other pictures I see of this engine the pump is connected?

8.5 compression is too Ralph Nader for me...I'd bring it up to 9.0-10.25....any more than that may be pushing it.

I don't know about the bell-housing pattern from Buick to Caddy...I'd check on some Caddy forums to glean some part #s, and see if they cross-reference to the part # for the ST400 bell-housing. If they match, you're golden. If not, then dig a little deeper & weigh your options.

My friend's family in NY had a 71 Fleetwood Brougham with the 472...6000 lbs of power & supreme comfort. Damn could that boat take off.

Sean I seen in past post you've done about the cadillac, what pistons did you go with?

Lemme the only thing I like about my compression is that I could shoot it with no2. I was told this engine was the 1968 10.1 but the guy lied to me.

That's great!

Click to expand...

With all the great BBB parts coming out a lot of those parts will cross over to use in a BB Caddy. Parts like the new 470 rods that have the BBC rod journal size of 2.2o" BUT the Caddy crank will need to have the rod journals to be taken down to 2.20" from 2.500", so while you're having that done you might as well have them add .300" of stroke to go from 4.0625" to 4.3625" stroke or with the new 482 BBB rods the crank can go to 4.4625" stroke!

The 472 Caddy has a bore size of 4.300, so with a .050" overbore the BBB pistons can be used as well. The deck height of the Caddy 472 is 10.8125", so with the 6.800" BBB rods and a stroked crank with a 4.465" stroke(4.365"/2 = 2.1825")

10.8125" - 6.800" = 4.125"- 2.2325 = 1.780" compression distance piston. Or with the 4.365" stroke that is .100" less, divide the difference by 2 = .050" and add that to the compression distance which would be 1.830".

The BBB rods are .003" thicker on the big end, not sure if they have the correct offset either so that is something to figure out as well if you like this route.

OR these Oldsmobile 455 rods may be a direct fit if they have the correct offset;

They are .065" shorter and you can't add stroke so the piston will need a taller compression ratio, the wristpin size is .980" instead of the BBC size the BBB aftermarket rods have which is .990". The wristpin can be opened to one of the sizes or if you get AutoTech pistons you can order the wristpin size you need.

With the standard stroke and the Olds rods the compression distance would need to be 10.8125"- 6.735" = 4.0775 - 2.03125 = a 2.046" compression distance to get to zero deck. IIRC I think TA sells 2.00" compression distance BBB pistons, so have deck machined .041" and tada! That will leave you .005" in the hole safety margin and with a .040" composite gasket will give you .045" of quench, just right.

Caddy 429-472-500s are awesome engines. They are super stout, reliable, and extremely light for their cubic inches. I've built a few, and they can be made into 500 hp 600 ft-lb monsters very easily, with ported stock heads. As stated, you don't need any more gear than 3.08. Even in my stock 5600 lb. '70 Coupe DeVille (which is rated at 375 hp 525 ft-lb stock) with 2.93 rear diff, it'll blow the tires off. Lots of places that specialize only in that specific engine, just Google away.

The one I have now is totally stock, but in those others, yes we built custom 1 3/4" headers. I always used the Edelbrock Performer for an intake. Check out 500cid.com and cad500parts.com (check out the Tech section on that one. Lots of good free info there.) There's even direct swap kits to put one in a G-body, which I always thought would be bitchin'......